How Accurate Is My Laser Scanner Really?
A Practical Evaluation Using Point Cloud Software
As part of a student project at HTW Dresden, Jannes, a student of Geomatics, set out to answer a key question: How accurate is the Lixel L2 Pro mobile laser scanner from XGRIDS really? Together with Laserscanning Europe, he developed a comprehensive testing setup to evaluate the absolute geometric accuracy of the scanner in both indoor and outdoor environments. The tools PointCab Origins and CloudCompare played a central role in analysis, visualization, and validation.
Objective:
Reliable Accuracy Through Comparison and Validation
The project investigated:
- Indoor and outdoor precision of the L2 Pro
- Comparison with a FARO Focus as a reference device
- Influence of control points (GCPs) on accuracy
- Point cloud comparison using CloudCompare
- Distance and section analyses with PointCab Origins
The main question:
Does the scanner meet the ±3 cm accuracy claimed by the manufacturer – and under what conditions?
Indoor Test:
Controlled Conditions for Clear Results
In a hall at HTW Dresden, the L2 Pro was tested first without, then with, four control points. Faro checkerboard targets with known 3D coordinates were used to calculate spatial distances.
Results:
- Without control points: Ø 9.2 mm deviation
- With control points: Ø 5.3 mm deviation
- Accuracy improvement through GCPs: ≈ 4 mm
Vertical accuracy – often problematic with mobile scanners – was also analyzed. In contrast to the smaller K1, the L2 Pro showed no significant vertical deviations, even in critical zones.
Analysis with PointCab Origins:
More Than Just Visualization
For evaluation, Jannes used PointCab Origins – especially for:
- Section views
- Distance measurements
- Elevation differences
In several sections at 5 mm resolution, barely any deviations were found between the L2 Pro cloud and the FARO reference. Only at highly reflective surfaces (e.g., ventilation ducts), deviations of up to 2.9 cm appeared – still within specification.
- Good to know: Further Insight from the Field
Sebastian Zell, managing director of a Berlin-based specialist in architectural surveying, also underlines the importance of PointCab Origins for quality assurance:
“We use PointCab Origins to reliably and visually verify whether our point clouds are correctly registered – especially on large-scale projects.”
PointCab Origins proved invaluable in this project too: the software enables users to identify deviations at a glance – a key advantage for safe handover to CAD or BIM.
Watch the related video (GERMAN):
👉 Die perfekte Registrierung – Interview 1/3 | Punktwolken Software, Zielmarken, 3D-Laserscanner
Outdoor Test:
Accuracy in Real-World Conditions
A 600 m loop was scanned using the L2 Pro to evaluate how the distribution of GCPs (Ground Control Points – permanently surveyed points in the field) affected results:
- Scenario 1: GCP spacing < 100 m
→ RMSE horizontal: 2.6 cm | vertical: 0.4 cm - Scenario 2: GCP spacing > 100 m
→ RMSE horizontal: 3.2 cm | vertical: 1.2–1.5 cm - Scenario 3: Poorly distributed GCPs
→ RMSE vertical: up to 14 cm
Conclusion: a strategic and dense placement of GCPs is essential for overall accuracy – especially for mobile scanners using SLAM technology.
CloudCompare: Making the Numbers Visible
CloudCompare was also used alongside PointCab Origins to:
- Directly compare point clouds (Cloud-to-Cloud Distance)
- Visualize deviations using color mapping
- Distinguish differences in mm and cm ranges
Result: The L2 Pro point cloud stayed well below the 3 cm tolerance across large areas, often under 1.5 cm – confirming its suitability for precise as-built documentation.
Conclusion:
Quality Requires Verification – And the Right Tools
The project clearly shows: modern scanners like the L2 Pro can produce highly accurate results with the right workflow. But it’s only through tools like PointCab Origins and CloudCompare that the true reliability of the data becomes clear and measurable.
PointCab Origins offers:
- Visual validation via intuitive section views
- Direct distance and elevation comparisons
- Confidence before CAD or BIM handover
If you aim for precision, you must not only capture your data – but verify it.
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